Bug#232448: debian-policy: Ada Library Information files must be read-only

[Ludovic Brenta <ludovic.brenta@insalien.org>]

Steve Langasek <vorlon@debian.org> writes:

> I don't see that this is a very good reason for an exception to the
> rules on file permissions.  Why can't gnat be fixed so that it doesn't
> try to auto-create object files when it shouldn't?

Because this would break the documented behaviour of GNAT and thus
make Debian incompatible with other distributions:

`-a'
     Consider all files in the make process, even the GNAT internal
     system files (for example, the predefined Ada library files), as
     well as any locked files. Locked files are files whose ALI file is
     write-protected.  By default, `gnatmake' does not check these
     files, because the assumption is that the GNAT internal files are
     properly up to date, and also that any write protected ALI files
     have been properly installed. Note that if there is an
     installation problem, such that one of these files is not up to
     date, it will be properly caught by the binder. [...]

(see http://gcc.gnu.org/onlinedocs/gcc-3.3.2/gnat_ug_unx/Switches-for-gnatmake.html#Switches%20for%20gnatmake)

With Debian packages, the write-protected ALI files have indeed been
properly installed and we want to tell GNAT not to check them for
consistency.  Failing to do this results in useless recompilations and
defeats the purpose of providing precompiled libraries.  (it is
possible to cause these useless recompilations to write to the current
directory instead of the directory where *.ali files are, though).

-- 
Ludovic Brenta.